Collapsible fin assembly



Jan. 28, 1947. H. c. WOLF 2,414,344

COLLAPS IBLE FIN ASSEMBLY Filed July 5, 1945 3' Sheets-Sheet l HowardE-Wn1f Jan. 28,

1947. H. c. WOLF COLLAPS IBLE FIN ASSEMBLY Filed July 5. 1943 3Sheets-Sheet 2 Howard E-Wn1f aammwa OWL-M Jan. 28, 1947. H. c. WOLFCOLLAPSIBLE FIN ASSEMBLY Filed July 5, 1943 3 Sheets-Sheet 3 Hnwar'dE-WD1 Patented Jan. 28, 1947 UNITED STATES PATENT OFFICE (Granted underthe act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) 11Claims.

The invention described herein may be manufactured and used by or forthe Government for governmental purposes without the payment to me ofany royalty thereon.

This invention relates to bombs and other missiles, and moreparticularly to the fins or tail fins secured to them for the purpose ofstabilizing their flight. The object of this invention is to devise afin assembly which may be readily applied to the bomb or other missileat the time the bomb is to be released from aircraft or at the time ofother discharge or firing. In present practice the fin assembly isshipped separately from the bomb and secured thereto at the place andtime of use. The fin assemblies heretofore used occupied considerablestorage space when crated for shipment. An important object of thisinvention is to devise a fin assembly which will occupy veryconsiderably reduced space in crated' condition and in shipping. Alliedwith this object, a further object is to device a fin assembly which isquickly and easily secured on the bomb Without the use of any specialtools and without any modification of the bomb.

For the attainment of these and such other objects as may appear or bepointed out I have shown an embodiment of my invention in theaccompanying sheet of drawings wherein:

Fig. 1 is an isometric view of the improved fin assembly in position ona bomb.

Fig. 2 is a top view of the fin assembly, the distal ends of the vanesnot being shown.

Figs. 3 and 4 are respectively, front view and top view of the sidepieces of the improved assembly.

Figs. 5 and 6 are respectively, front view and top view of the vanes ofthe improved assembly.

Figs. 7a, 7b, and 7c are respectively, the top, side and front views ofa bracket member employed in locking the fin assembly in open condition.

Fig. 8 is a front view of the ring member employed, in conjunction withthe bracket member in locking the fin assembly in open condition.

Fig. 8a is a perspective view of the ring member.

Fig. 9 shows the improved fin assembly in folded condition.

Fig. 10 is a sectional view of the upper portion of the bomb and thelower portion of the fin assembly, showing the manner of attachment.

The improved fin assembly comprises four side pieces I 0 and four vanes20 which are located at the four corner edges presented by the four sidepieces when assembled in the box-like formation shown in Figs. 1 and 2.At each of the said four corner edges two side pieces Ill and a singlevane 20 are articulated or hinged together by a single pintle 30. Forthis purpose one edge of the vane 20 is provided with ears 2|conveniently made by bending the sheet metal of which the vanes arefabricated. Both edges of the side pieces H) are provided with similarlyformed ears l2 and I3. It will be observed from Fig. 3 that while theears l2 and I3 on the two edges may be of substantially the same widths,the ears, e. g. l2 are not in alignment with the ears 13 of the otheredge. This is to provide for the interlocking of the ears of the threemeeting edges, namely the proximal edge of the vane, one edge of oneside piece, and the opposite edge of an adjacent side piece. It will beobserved from Fig. 5 that the ears of the two adjacent side pieces andthe single vane follow one another in the following repeated sequence:an ear [3 of one edge of one of the adjacent side pieces, an ear I2 fromthe opposite edge of the other of the adjacent side pieces, and. an ear2| of the vane.

For the purpose of providing means enabling the improved fin assembly tobe locked in open or operative position the lower portion of each vane20 is provided with a bracket 23 which is conveniently spot-welded toturned edge 22 at the lower vane portion. A detail enlargement ofbracket 23 is shown in Figs. 7a, 7b, and where it will be seen that thebracket is stamped in the form of an inverted-L, the vertical leg 24 ofwhich is considerably longer than the horizontal leg 25 and is thesurface which is spot-welded to vane edge 22. As best seen in Fig. 7c,the horizontal leg 25 is stamped in the form of an inverted-U. A bracingweb 26 is left between the two legs, Fig. lb, or rather a pair of suchwebs, at the sides of the bracket, Fig. 7c. The distal edge of thehorizontal leg 25 of the bracket is provided with a pair of ears 21, oneon each side, which project laterally from the horizontal leg, as bestseen in Fig. 7a. As the top view of Fig. 7a reveals, the horizontal leg25 presents a T-formation with the ears 21 constituting the lateralprojections and distally disposed. The horizontal leg 25 extends pastthe formation of the ears 2'! to provide a slight extending portion 28.

The brackets 23, more particularly, the T- shaped horizontal leg 25,cooperate with a ring 40 having concentric edge flanges 4! so as topresent an inverted-U cross-section. The ring, or rather its pair ofconcentric edge flanges 4|, is provided with four notches 42 spaced fromeach other. The width of the notches 42 is only slightly greater thanthe width of the horizontal T-shaped leg 25 of the bracket 23 to allowthe assembly of these two parts to form a tight fit, one with the other.The inside width of the ring, i. e., the inside distance between theconcentric edge flanges 4| (dimension R, Figs. 8 and 2), is somewhatwider than the width of the ears 2'! (dimension E, Fig. 7a).

The fin is assembled from the flat position shown in Fig. 9 so that theside pieces IE! form a square and the vanes bisect the 90 angle formedby the sides. The ring 40 is snapped into position so that the ears 2!of the brackets 23 engage between the edge flanges M of the ring 40, andthe extending portion 28 and the horizontal portion in front of and tothe rear of the ears 21, respectively, engage with the cut-out sections42 on the edge flanges M. The assembled fin is then placed over the tailof the bomb, as shown in Figure 10, so that the extremities 29 of thebracket 23 come in contact with the tapered por tion of the bomb tail 1.The fin lock-nut 2 is then screwed onto the base plug 3 so that theguide lip 11 of the nut 2 centers the fin assembly by engaging thecentral'portion of the locking ring 40. The fln lock-nut 2 tightens upthe fin assembly by contacting the locking ring 40 which transmits theforce to the extremities 29 of the brackets 23. Any looseness which mayoccur is compensated for by the wedging action which results in aself-tightening efiect.

I claim:

1. A collapsible fin assembly for a bomb comprising four side-piecesformed of sheet material, the said material being bent along twoparallel edges to form integral hinge ears, four vanes formed of sheetmaterial, the said material being bent along one edge to form integralhinge ears, the said hinge ears of the two edges of the sidepieces andof the single edge of the vane being aligned relative to each other sothat the ears of all three said edges will interlock to form acontinuous hinge, pintles therefor adapted to hold the said eight partswhen opened up in the form of a square formed of the said foursidepieces with a vane projecting outwardly from each of the fourcorners thereof in a direction to bisect the right-angle at the saidcorners of the square, the said parts being adapted to fold at theirsaid four hinges to be collapsed into a substantially fiat shape, eachof the lower portions of the vanes having a downwardly directed inclinedextension presenting an edge parallel to the hinge edge of the vane,brackets in the shape of an inverted-L, formed from sheet material inthe form of a channel with inwardly-turned flanges along the edges, thelonger vertical leg of the brackets being spot welded to the said edgeof the vane extensions, the shorter horizontal leg of the bracketpresenting its channel section as an inverted-U, the material of thesaid side flanges being enlarged between the said horizontal andvertical legs to form a reinforcing brace, the flange material beingfurther enlarged at the distal end of the horizontal leg and formed asupturned lateral ear projections extending for a predetermined lengthalong both sides of the horizontal leg, and a ring formed of sheet metalin the form of an inverted-U channel, the inside distance be tween theflanges thereof being somewhat greater than the said predeterminedlength of the distal ear projections of the horizontal leg of thebracket, the said channeled ring being provided with four equi-distancedcut-outs in both its said channel flanges, the said ring cut-outs beingsomewhat larger than the width of the said bracket whereby the ring maybe slipped over the said four vanes when in their said opened position,the said lateral ear projections being received in the channel of thering to lock the vanes and the said ring in the said open position ofthe assembly.

2. A collapsible fin assembly for a bomb comprising four side-piecesformed of sheet material, the said material being bent along twoparallel edges to form integral hinge ears, four vanes formed of sheetmaterial, the said material being bent along one edge to form integralhinge ears, the said hinge ears of the two edges of the sidepieces andof the single edge of the vane being aligned relative to each other sothat the ears of all three said edges will interlock to form acontinuous hinge, pintles therefor adapted to hold the said eight partswhen opened up in the form of a square formed of the said fourside-pieces with a vane projecting outwardly from each of the fourcorners thereof in a direction to bisect the right-angle at the saidcorners of the square, the said parts being adapted to fold at theirsaid four hinges to be collapsed into a substantially flat shape, eachof the lower portions of the vanes having a downwardly directed inclinedextension presenting an edge parallel to the hinge edge of the vane,brackets in the shape of an inverted-L, formed from sheet material inthe form of a channel with inwardly-turned flanges along the edges, thelonger vertical leg of the brackets being secured to the said edge ofthe vane extensions, the shorter horizontal leg of the bracketpresenting its channel section as an inverted-U, the material of thesaid side flanges being enlarged between the said horizontal andvertical legs to form a reinforcing brace, the flange material beingfurther enlarged at the distal end of the horizontal leg and formed asupturned lateral ear projections extending for a predetermined lengthalong both sides of the horizontal leg, and a ring formed of sheet metalin the form of an inverted-U channel, the inside distance between theflanges thereof being somewhat greater than the said predeterminedlength of the distal ear projections of the horizontal leg of thebracket, the said channeled ring being provided with four equi-distancedcut-outs in both its said channel flanges, the said ring cut-outs beingsomewhat larger than the width of the said bracket whereby the ring maybe slipped over the said four vanes when in their said opened position,the said lateral ear projections being received in the channel of thering to lock the vanes and the said ring in the said open position ofthe assembly.

3. A collapsible fin assembly for a bomb comprising four side-piecesformed of sheet material, the said material being bent along twoparallel edges to form integral hinge ears, four vanes formed of sheetmaterial, the said material being bent along one edge to form integralhinge ears, the said hinge ears of the two edges of the sidepieces andof the single edge of the vane being aligned relative to each other sothat the ears of all three said edges will interlock to form acontinuous hinge, pintles therefor adapted to hold the said eight partswhen opened up in the form of a square formed of the said foursidepieces with a vane projecting outwardly from each of the fourcorners thereof in a direction to bisect the right-angle at the saidcorners of the square, the said parts being adapted to fold at theirsaid four hinges to be collapsed into a substantially fiat shape,brackets in the shape of an inverted-L, and formed from sheet materialin the form of a channel with inwardly-turned flanges along the edges,the longer vertical leg of the bracket being secured to an edge of thesaid vanes, the shorter horizontal leg of the bracket presenting itschannel section as an inverted-U, the material of the said side flangesbeing enlarged between the said horizontal and vertical legs to form areinforcing brace, the flange material being further enlarged at thedistal end of the horizontal leg and formed as upturned lateral earprojections extending for a predetermined length along both sides of thehorizontal leg, and a ring formed of sheet metal in the form of aninverted-U channel, the inside distance between the flanges thereofbeing somewhat greater than the said predetermined length of the distalear projections of the horizontal leg of the bracket, the said channeledring being provided with four equidistanced cut-outs in both its saidchannel flanges, the said ring cut-outs being somewhat larger than thewidth of the said bracket whereby the ring may be slipped over the saidfour vanes when in their said opened position, the said lateral earprojections being received in the channel of the ring to lock the vanesand the said ring in the said open position of the assembly.

4. A collapsible fin assembl for a bomb comprising four side-piecesformed of sheet material. the said material being bent along twoparallel edges to form integral hinge ears, four vanes formed of sheetmaterial, the said material being bent along one edge to form integralhinge ears, the said hinge ears of the two edges of the side-pieces andof the single edge of the vane being al gned relative to each other sothat the ears of all three said edges will interlock to form acontinuous hinge, pintles therefor adapted to hold the said eight partswhen opened up in the form of a square formed of the said foursidepieces with a vane projecting outwardly from each of the fourcorners thereof in a direction to bisect the right-angle at the saidcorners of the square, the said parts being adapted to fold at theirsaid four hinges to be collapsed into a substantially flat shape,brackets in the shape of an inverted-L, and formed from sheet materialin the form of a channel with inwardly-turned flanges along the edges,the longer vertical leg of the bracket being secured to an edge of thesaid vanes, the shorter horizontal leg of the bracket presenting itschannel section as an inverted-U, the flange material being furtherenlarged at the distal end of the horizontal leg and formed as upturnedlateral ear projections extending for a predetermined length along bothsides of the horizontal leg, and a ring formed of sheet metal in theform of an inverted-U channel, the inside distance between the flangesthereof being somewhat greater than the said predetermined length of thedistal ear projections of the horizontal leg of the bracket, the saidchannel ring bein provided with four equi-distanced cut-outs in both itssaid channel flanges, the said ring cutouts being somewhat larger thanthe width of the said bracket whereby the ring may be slipped over thesaid four vanes when in their said opened position, the said lateral earprojections being received in the channel of the ring to lock the vanesand the said ring in the said open position of the assembly.

5. A collapsible fin assembly for a bomb comprising four side-piecesformed of sheet material, the said material being bent along two parallel edges to form integral hinge ears, four vanes formed of sheetmaterial, the said material being bent along one edge to form integralhinge ears, the said hinge ears of the two edges of the sidepieces andof the single edge of the vane being aligned relative to each other sothat the ears of all three said edges will interlock to form acontinuoushinge, pintles therefor adapted to hold the said eight parts when openedup in the form of a square formed of the said four sidepieces with avane projecting outwardly from each of the four corners thereof in adirection to bisect the right-angle at the said corners of the square,the said parts being adapted to fold at their said four hinges to becollapsed into a substantially flat shape, each of the lower portions ofthe vanes having a downwardly directed inclined extension presenting anedge parallel to the hinge edge of the vane, bracketsin the shape of aninverted-L, formed from sheet material in the form of a channel withinwardly-turned flanges along the edges, the longer vertical leg of thebrackets being spot welded to the said edge of the vane extensions, theshorter horizontal leg of the bracket presenting its channel section asan inverted-U, the material of the said flanges being enlarged betweenthe said horizontal and vertical legs to form a reinforcing brace, theflange material being further enlarged at the distal end of thehorizontal leg and formed as upturned lateral ear projections extendingfor a predetermined length along both sides of the horizontal leg, and aring formed of sheet metal in the form of an inverted-U channel, theinside distance between the flanges thereof being somewhat greater thanthe said predetermined length of the distal ear projections of thehorizontal leg of the bracket, the said channeled ring being providedwith four equi-distanoe'd cutouts in the outer channel flanges, thesaidring cut-outs being somewhat larger than the width of the saidbracket whereby the ring may be slipped over the said four vanes when intheir j said opened position, the said lateral ear projections beingreceived in the channel of the ring to lock the vanes and the said ringin the said open position of the assembly. I

6. A collapsible fin assembly for a bomb comprising four side-piecesformed of sheet material, the said material being bent along twoparallel edges to form integral hinge ears, four vanes ,fcrmed of sheetmaterial, the said material being bent along one edge to form integralhinge ears, the said hinge ears of the two edge of the sidepieces and ofthe single edge of the vane being aligned relative to each other so thatthe ears of all three said edges will interlock to form a continuoushinge, pintles therefor adapted to hold the said eight parts when openedup in the form of a square formed of the said four sidepieces with a,vane projecting outwardly from each of the four corners thereof in adirection to bisect the right-angle at the said corner of the square,the said parts being adapted to fold at their said four hinges to becollapsed into a substantially flat shape, each of the lower portions ofthe vanes having a downwardly directed extension presenting an edgeparallel to the hinge edge of the vane, a bracket in the shape of aninverted-L, the longer vertical leg of the bracket being spot welded tothe said edge of the vane extension, the horizontal leg of the bracketbeing enlarged at its distal end of the horizontal leg to form lateralprojections extending for a, predetermined length along both sides ofthe horizontal leg, and a ring formed of sheet metal in the form of aninverted-U channel, the inside distance between the flanges thereofbeing somewhat greater than the said predetermined length of the distalprojections of the horizontal leg of the bracket, the said channeledring being provided with four equi-distanced cut-outs, the said ringcut-outs being somewhat larger than the width of the said bracketwhereby the ring may be slipped over the said four vanes when in theirsaid opened position, the said lateral projections being received in thechannel of the ring to lock the vanes and the said ring in the said openvane position.

'7. A collapsible fin assembly for a bomb comprising four side-piecesformed of sheet material, the said material being bent alon two paralleledges to form integral hinge ears, four vanes formed of sheet material,the said material being bent along one edge to form integral hinge ears,the said hinge ears of the two edges of the sidepieces and of the singleedge of the vane being aligned relative to each other so that the earsof all three said edges will interlock to form a continuous hinge,pintles therefor adapted to hold the said eight parts when opened up inthe form of a square formed of the said four side-pieces with a vaneprojecting outwardly from each of the four corners thereof in adirection to bisect the right-angle at the said corners of the square,the said parts being adapted to fold at their said four hinges to becollapsed into a substantially flat shape, and a ring adapted to hslipped over the bomb, the said rin and the said four vanes beingprovided with cooperative means to hold the vanes in their said openedposition.

8. A collapsible fin assembly for a bomb comprising four side-piecesformed of sheet material, the said material being bent along twoparallel edges to form integral hinge ears, four vanes formed of sheetmaterial, the said material being bent along one edge to form integralhinge ears, the said hinge ears of the two edges of the sidepieces andof the single edge of the vane being aligned relative to each other sothat the ears of all three said edges will interlock to form a continuous hinge, pintles therefor adapted to hold the said eight partswhen opened up in the form of a square formed of the said fourside-pieces with a vane projecting outwardly from each of the fourcorners thereof in a, direction to bisect the right-angle at the saidcorners of the square,

each vane having a portion extending below its hinge the said part beingadapted to fold at their said four hinges to be collapsed into asubstantially flat shape, and means cooperating with said extended vaneportion for locking the vanes in their said open position.

9. A collapsible fin assembly for a bomb comprising four side-piecesformed of sheet material, the said material being bent along twoparallel edges to form integral hinge ears, four vanes formed of sheetmaterial, the said material being bent along one edge to form integralhinge ears, the said hinge ears of the two edges of the sidepieces andof the single edge of the vane being aligned relative to each other sothat the ears of all three said edges will interlock to form acontinuous hinge, and pintles therefor adapted to hold the said eightparts when opened up in the form of a square formed of the said foursidepieces with a vane projecting outwardly from each of the fourcorners of the square, each vane having a portion extending below itshinge, the said parts being adapted to fold at their said four hinges tobe collapsed into a substantially flat shape, and means cooperating withsaid extended vane portion to lock the vanes in their open position.

10. A foldable fin assembly for a bomb having a tapered bomb tail and afin lock nut, comprising a plurality of vanes, brackets in the shape ofan inverted-L, the longer legs of which are secured to the lower portionof the vanes, a ring provided with means for engaging the horizontallegs of the said brackets, the said horizontal legs of the bracketshaving lower end extremities adapted to contact the said tapered tail ofthe bomb, and the said bracket engaging ring being adapted to underliethe said fin lock nut of the bomb whereby the screwing of the lock nuton the bomb will force the said bracket extremities to bear firmlyagainst the said tapered tail of the bomb.

11. A collapsible fin assembly for attachment to the tail portion of abomb, comprising plates hinged at their edges to form a square, and atleast one outwardly extending vane hinged to each corner of the squareand having a hinge line common with the hinge line of the intersectingplates forming the corner, said vanes each having a portion extendedbelow its hinged edge, and a ring adapted to surround the tail of a bomband provided with notches entered by said extended portions to lock saidassembly in open position.

HOWARD C. WOLF.

